This invention relates to the art of making snow for ski resorts and the like. More particularly, it relates to improvements in snow-making apparatus so that large volumes of high quality snow can be produced where needed with minimal operator involvement.
Though the art of snow-making has been known for several decades, the application of the art to the business of making snow at ski resorts has presented many challenges. While it's a relatively simple matter to combine water and compressed air in such a manner as to produce, under controlled conditions, a uniform blanket of "high quality" snow (i.e. snow having a desirable moisture content), it's considerably more difficult to produce such snow on a mountan top where the terrain is steep, the winds shift and the temperature and humidity frequently undergo the type of change that affects the quality of the snow produced. For example, it is not uncommon to discover in the morning following a night of snow-making that, as a result of a wind shift or unexpected temperature rise, most of the artificial snow made has either been blown into the woods adjacent the ski trail intended for the deposit, or become so laden with moisture that the "slushy" deposit has frozen to a treacherous mass that, prior to skiing, must either be pulverized or covered over. In either case, most of the cost of the previous night's snow-making operation has been wasted.
To help cope with changing weather conditions so that the snow-making effort more closely matches the intended results, many ski resorts maintain large crews of equipment operators. Much of the time of these crews is occupied in tending the "snow-guns", i.e. the snow-making devices which combine water and compressed air in the requisite manner to produce a spray of ice crystals. Obviously, the spray of these guns should always be aimed in a direction to compensate for windage; otherwise, the snow deposit will miss its mark. Also, the ratio of the water and compressed air should always be set on the basis of the present temperature and relative humidity; otherwise, the snow consistency will be either too wet or too dry. As temperatures increase, for example, less water is needed to achieve a nominal snow consistency or quality. As described below, both of these tasks are relatively labor-intensive and, as as result, add considerably to the cost of snow-making.
In the process of tending the snow-guns, it is common for teams of two people to work together in making the adjustments necessary to achieve a desired pattern of coverage and a desired snow consistency. Typically, each snow-gun is disposed on an adjustable mount that provides for manual azimuth and elevation adjustments so that the direction in which the gun projects a spray of snow can be controlled. A detent arrangement on the gun mount, such as disclosed in U.S. Pat. No. 4,759,503, allows the operator to aim the gun in certain predetermined directions. In aiming the gun, it is common for one team member to make the manual adjustments while the other member checks the coverage pattern, as affected by the wind, and calls out instructions. Similarly, in achieving a desired snow consistency, one team member manually adjusts the valves used to control the water and air supplied to the gun in response to the directions of the other member who monitors the falling snow for consistency. Obviously, the need for two people to make such simple adjustments adds expense to the process and, to the extent possible, should be avoided.
French Pat. No. 2,573,854 to P. Girardin, discloses a computer-controlled system for remotely controlling the water-to-air ratio supplied to a plurality of snow-making sites. Based on the respective outputs of temperature and relative humidity sensors associated with each site, a computer controls the operation of a complex valving arrangement which controls both the water and air supply to an associated snow-gun. While such an automated system is theoretically capable of producing a desired snow consistency for a variety of weather conditions, experience shows that there is no substitute for first-hand sampling of the snow consistency at the time the water and/or air adjustments are made. Moreover, this system provides no means for automating the gun position adjustment to remotely control the direction of snow-making.